ApolloChoiceModelling forum

Hello,

#My estimate doesn't work when i run the following command:

model = apollo_estimate(apollo_beta, apollo_fixed, apollo_probabilities, apollo_inputs)

#It gives me the following error:

Error in rowsum.default(log(P), group = indivID) :
incorrect length for 'group'

#Thank you for your help in advance.

#For reference, here is my entire code:
library (apollo)
apollo_initialise()

library (haven)

##Reading excel sheet
database <- read_excel("database.xls")

# ################################################################# #


apollo_control = list (
modelName ="DK_ce",
modelDescr = "The updated data specific to Denmark",
indivID = "id"
)


###Defining the model parameters
apollo_beta= c(asc_status_quo=0,
asc_program_A=0,
asc_program_B=0,
b_cost_a=0,
b_quality_a=0,
b_plastic_a=0,
b_location_a=0,
b_measure_a=0,
b_certainty_a=0,
b_cost_b=0,
b_quality_b=0,
b_plastic_b=0,
b_location_b=0,
b_measure_b=0,
b_certainty_b=0,
b_cost_c=0,
b_quality_c=0,
b_plastic_c=0,
b_location_c=0,
b_measure_c=0,
b_certainty_c=0
)

apollo_fixed= c("asc_status_quo")
#Group and validate inputs
apollo_inputs = apollo_validateInputs()

###Define model and liklihood function

apollo_probabilities=function(apollo_beta, apollo_inputs, functionality="estimate"){

# Attach inputs and detach after function exit (allows to call variables without referring to dataset)
apollo_attach(apollo_beta, apollo_inputs)
on.exit(apollo_detach(apollo_beta, apollo_inputs))

# Create list of probabilities P
P = list()

# List of utilities: these must use the same names as in mnl_settings, order is irrelevant
V = list()
V[['status_quo']] = asc_status_quo + b_cost_c * cost_c + b_quality_c * quality_c + b_plastic_c * plastic_c + b_location_c * location_c + b_measure_c * measure_c + b_certainty_c * certainty_c
V[['program_A']] = asc_program_A + b_cost_a * cost_a + b_quality_a *quality_a + b_plastic_a * plastic_a + b_location_a * location_a + b_measure_a * measure_a + b_certainty_a * certainty_a
V[['program_B']] = asc_program_B + b_cost_b * cost_b + b_quality_b *quality_b + b_plastic_b * plastic_b + b_location_b * location_b + b_measure_b * measure_b + b_certainty_b * certainty_b

# Define settings for MNL model component
mnl_settings = list (
alternatives = c(status_quo = 0, program_A = 1, program_B = 2),
avail = 1 ,
choiceVar = choice ,
V = V
)
##Estimating the multinomial logit

# Compute probabilities using MNL model
P[['model']] = apollo_mnl(mnl_settings, functionality)

# Take product across observation for same individual
P = apollo_panelProd(P, apollo_inputs, functionality)

# Prepare and return outputs of function
P = apollo_prepareProb(P, apollo_inputs, functionality)
return(P)
}


# MODEL ESTIMATION

model = apollo_estimate(apollo_beta, apollo_fixed, apollo_probabilities, apollo_inputs)

Hi

this error seems to happen in your case as the data is an Excel file. If you save the Excel file as csv and read that in, it works fine. I would always recommend working with csv instead of Excel for your data files

Stephane